The present invention relates to a method of opening a lid of a box including a main body and a lid which is freely openable and closable with respect to the main body, and the device for the same method.
In general, as means for packing goods, a box is used and, in a factory, goods such as a large quantity of foods or the like are packed in a given packing line. In such packing line, a box for packing the foods is supplied with its lid closed condition and, in particular, in the packing line of the factory, it is demanded that the lids of the boxes are opened from the main bodies of the boxes automatically, in a large quantity and at a high speed.
For example, in FIG. 30, reference numeral 1 designates for a box. The box 1 includes a box main body 2 formed of cardboard and having an opening 2A in one of the side portions thereof, and a lid 3 formed of cardboard and having vertical portions 3A, the lid 3 being adapted to be put over the opening 2A of the box main body. The vertical portions 3A of the lid 3 are superimposed on the peripheries of the side surface portions 2B of the main body 2 respectively so that the lid 3 can be opened and closed freely. And, the box main body 2 is formed to be strong because it is used to pack bottles or the like. On the surface of the lid 3, there are printed the name of the manufacturer, the name of the goods, a decorative design and the like. As compared with the box main body 2, the lid 3 is smaller in thickness and the vertical porions 3A of the lid 3 are relatively flexible.
However, in the conventional method, when the lids of boxes supplied successively on a packing line are opened from the main bodies of the boxes, the lids opening operation is executed manually by an operator manual and, therefore, it is difficult to open a large quantity of the lids of the boxes in a short time.
In FIGS. 31 to 33, there is shown an embodiment of a method for opening the lid 3 of the above-mentioned box 1 by hand.
As shown in FIG. 31, if an operator grasps the vertical portions 3A of the lid 3 of the box 1 by both hands and lifts up the whole box 1, then the box main body 2 will slip down to some extent due to its own weight and thus will take a position as shown by dotted chained lines. And, as shown in FIG. 32, with the main body 2 in such position, while holding the main body 2 with one hand 4, the operator grasps the lid 3 with the other hand 4 and then removes the lid 3 upwardly from the main body 2. When one of the vertical portions 3A of the lid 3 is removed from the main body 2, then the lid 3 is inclined in a state as shown in FIG. 33.
In view of this, as means for automating the opening of the lids of the boxes, there is also known a method in which the lid of the box is opened from the main body of the box by suction applied to the top plate of the lid by suction pads. According to the lid opening method by use of the suction pads, for example, as shown in FIGS. 36 and 37, the four corner portions of a lower surface 102A of a main body 102 of a box 101 are respectively sucked by main body suction pads 105 (only two of them are shown) and, the four corner portions of an upper surface 103B of a lid 103 of the box 101 are respectively sucked by lid suction pads 106. Next, if the main body suction pads 105 are pulled downwardly and at the same time the lid suction pads 106 are pulled upwardly, then the lid 103 can be separated from the main body 102.
However, in the former example in which the lid is opened manually by the operator, it is necessary for the operator to grasp the lid 3 by hands 4 and to wait for the box main body 2 to slip down to some extent due to its own weight before the lid 3 can be opened completely. This requires a long time to open the lid 3.
Alternatively, in the later example of the lid opening method by use of the suction pads 105 and 106, when trying to separate the lid 103 and main body 102 from each other, the vertical portions 103A of the lid 103 are flexed inwardly or in an inwardly caving manner to closely contact the side surface portions 102B of the main body 102, which makes it difficult for air to flow into the box 101. As a result of this, the internal pressure of the box 101 is decreased to thereby cause the box 1 to be pushed inwardly by the external pressure thereof, which makes it difficult for the lid 103 to be opened and thus extends a time necessary to open the lid 103.
Also, when trying to open the lid 103 quickly, the upper surface 103B of the lid 103 is flexed to a great extent to thereby leave wrinkles and the traces of the suction pads on the four corners of the upper surface 103B of the lid 103.